Chair back structure and a mounting usable therein



March 1, 1960 J. o. ECKMANN 2,926,725

CHAIR BACK STRUCTURE AND A MOUNTING USABLE THEREIN Filed 06$. 25, 1956 IN VEN TOR.

. 7 JOSE/9H0. ECkM/qA/A Mai,

CHAIR BACK STRUCTURE AND MOUNTING USABLE THEREIN Joseph 0. Eckmann, Milwaukee, Wis., assignor, by inesne assignments, to Precision Metal Workers, Chicago, Ili.,

a partnership of Illinois Application October. 25, 1956, Serial No. 618,367

11 Claims. o1,1s-'-17s This invention relates toa chair back structure and a mounting usable therein, as well as for otherpurposes.

The mounting provides in simple and inexpensive form a flexible, resilient and silent support which can be made inexpensively and which finds a' particular utility in the connection of aback rest to an upright support to constitute the back of a chair. i

The back rest is of generally conventional design, being provided with a rearwardly facing boss and a corresponding forwardly opening pocket in which a .nut is fixed, desirably being welded to the back rest. Threaded through the back rest into. this nut is a standard eye bolt in which there is engaged the hook of a hook bolt. Any one of a variety of nut arrangements is threaded to the latter and engaged with the upright support of the chair and arranged, to subject to pressure an annular rubber cushion which surrounds the connection between the hook bolt and the eye bolt, therebyproviding a resiliently yieldable and universally flexible mounting supporting the back rest from the upright.

t In the drawings: I

Fig. 1 is a plan view of a back rest mounted in accordance with the present invention on the tubular bar which serves as the upright support at the back of a chair.

Fig. 2 is a view in front elevation of the parts shown in Fig. 1, the bar being fragmentarily illustrated.

Fig. 3 is an enlarged detail view in axial section through the elements of my improved mounting.

Fig. 4 is a detail view in horizontal section showing a preferred application of the mounting to support the backrest in the device of Figs. 1 and 2.

Figs. 5, 6 and 7 are fragmentary views similar to Fig. 4 showing various modified embodiments so far as the connection of, the hook bolt is concerned.

The vertical support portion of the chair back constitues a tube 10 which, in the present exemplification, is square in cross section. The generally elliptical back rest 11 is conventional, comprising forward and rearward walls 12 and 13'best shown in Fig. 4, the forward wall 12 being inwardly embossed at 14 to provide a pocket and the rearward wall having a corresponding boss at 15 to provide a surface engaged by the rubber cushion hereinafter described.

An eye bolt 16 extends through registering openings in boss' 15 and the rearwardly embossed portion of the cushionIZS, if desired.

2 V a heavy wall. It is also possible to mold the annular It is understoodthat any suitable elastomer material may be used to make the annular cushion, naturalior synthetic rubber being preferred, principallyfor reasons of economy and availability.

The head 20. of eye bolt 16 is provided within the cushion with an eye 26 whichis of greatly reduced; thickness as compared with the rest of the head in order to receive the hook 27 attached to the head 28 of a hook bolt 30. The resilient flexibility of the annular elastomeric cushion permits yielding, universallypivotal movement between hook 27 and eye'26 to accommodate. the flexing of the backrest with regard to support 10. Needless to say, the firmness of theelastomen'used in thecushion .will determine the degree of flexibility. In

'practiceyl have found it appropriate to use an extruded tube of natural rubber of approximately durometer.

The tubular support has an opening at 31 of willcient size to pass the hook bolt freely. The surface of the support aroulndjthe opening is engaged, by the end ofthe rubber cushion 25. In the preferredstructure, a tube nut 33 has its head 34 engaged with the opposite side of the support 10 and screwthreaded onto thehook bolt 30, as clearly shown in F ig, 4, to maintain the parts in assembly. The tube nut. maybe turned down to seat on shoulder 35 of the hook bolt. Upon such engagement,'however, the dimensions of the parts should be such thatthe elastomeric cushion 25 is subject tocom pression.

' Figs, 5, 6 andj show alternate ways in which the hook I bolt may be mounted upon thesupport. InFig. 5; the

.end portion 280 of the. hook bolt 300 extends partway through the support 10, its threaded end projecting through the back of the support and engaged by a nut 37. a In the construction of Fig. 6, the body portion 281 is socketed to receive a screw 38, the head of which is engaged behind support 10.

In the construction shown in Fig. 7, the hook bolt 30 is unchanged but, instead of being engaged by a tubular nut of the type shown in Fig. 4, it is threaded within a length of tubing 39 in which a screw 38 like that of Fig. 6 is engaged. understood that I may use any desired.type of lock washer.

The mounting unit separately illustrated in Fig. 3 is, of course, an articleof manufacture which can be made and sold in the unitary form in which it is shown.

I claim:

1. As a new'article of manufacture, a flexible mounting unit comprising an elastomeric annular cushion'having a central opening within which .a hook and eye are engaged, the hook and eye each being free of anchorage in the cushion and having head portions substantially titforward. wall 12 and is threaded into a nut 17 that in tomeric cushion 25 which is generally tubular and may comprise a short length of extruded rubber tubing with ting the opening and being respectively provided with further connecting portions projecting from said cushion at the ends of the opening.

2. As a new article of manufacture, a flexible mounting comprising a pair of members having heads of gen erally corresponding cross section and having hook and eye portions mutually engaged, an elastomeric cushion having a through opening fitting the cross section of the headportion of said members and within which said head portions are confined against relative lateral displacement other than such as isaccommodated by the flexing of the cushion, each said member being free of.

anchorage in the cushion and having a shoulder defining the end of its head portion and being provided therebeyond with threaded connecting portions, the said cushion extending at least substantially to the respective p ses Mar. 1,1963% In any of these constructions, it will be shoulders whereby substantially all of said head portions are housed within the cushion.

3. The device of claim 2 in which the cushion comprises a length of extruded rubber tubing of approximately 45 durometer test.

4. As a new article of manufacture, a mounting device comprising the combination with an annular elastomeric cushion having a central opening with portions extending to the ends of said cushion, of a pair of members, and means providing universally flexible connections therebetween entirely within the cushion, the said members being free of anchorage in the cushion and having head portions fitted in the said end portions of said opening where they are exposed for introduction and removal and having threaded connecting portions projecting from the cushion.

5. In a. chair back, the combination with a support and a back rest, of laterally spaced, resiliently flexible means connecting the back rest to the support and providing a yieldable mounting for the back rest on which the back rest is tiltable, each such means including an elastomeric annular cushion under axial compression and comprising members pivotally connected with each other within the cushion and having head portions fitted in the cushion, the respective members having screwthreaded terminal portions projecting from the cushion and respectively connected with the back rest and the support.

6. The device of claim 5 in which the respective members comprise an eye bolt and a hook bolt. 1

. 7. The device of claim 5 in which the cushion comprises a short length of extruded rubber tubing of approximately 45 durometer test.

8. The combination with a pair of apertured parts pression and having a central opening communicating with the apertures of said parts, elements having head portions fitted within the opening of the cushion and having means providing pivotal connection between said elements within the cushion, each such element having a screwthreaded portion extending into an aperture of one of said parts, and fastening means threaded on said portions to engage the respective parts.

9. The device of claim 8 in which one of said fastening means comprises a tubular nut with a threaded opening in which the screwthreaded portion of the respective element is engaged. I

10. The device of claim 8 in which said fastening means comprises a headed screw, the fastening means comprising a threaded socket in which the screw is engaged.

11. The device of claim 8 in which one of said parts is hollow and has aligned apertures, thesaid part being abutted by the annular cushion about one of the apertures, one screwthreaded portion extending through the last mentioned aperture to the interior of the hollow part, one fastening means being in engagement externally with the hollow ipart laterally adjacent its other apertureand being in threaded connection with said last screwthreaded portion.

References Cited in the file of this patent UNITED STATES PATENTS 1,683,330 Chilton Sept. 4, 1928 2,156,301 Loewus May 2, 1939 2,549,768 Bradley Apr; 24,1951 2,579,918 Freeman Dec. 25, 1951 2,611,423 Blum Sept. 23, 1952 2,636,552 Long Apr. 28, 1953 2,708,560 Paley. May 17, 1955 

